| Abstract: | A study designed to test the validity of an isotopic method for estimating evaporation was conducted within a small, tundra lake situated in the continental Arctic of Canada. Evaporation was determined using an isotope mass balance approach which accounted quantitatively for isotopic fractionation, progressive evaporative enrichment of δ18O and δ2H in lake water, and attenuation of enrichment by liquid inputs and atmospheric moisture. Concurrent determinations made using standard mass balance, energy balance, aerodynamic profile and class A pans permitted rigorous comparisons between methods. Results are presented for two summers which had distinct weather conditions and hydrological balances. Overall, the δ18O balance was found to be in good agreement with standard methods during both years over time intervals greater than about one week. Owing to a less systematic response of δ2H over short time periods, it use is not recommended for quantitative mass balance determinations over time intervals of less than about 50 days in this setting. |
